From f082a13ab756a378b260711a30d363f833a2306a Mon Sep 17 00:00:00 2001
From: Suhas Daftuar <sdaftuar@gmail.com>
Date: Mon, 29 Jun 2020 14:59:55 -0400
Subject: Disconnect peers sending wtxidrelay message after VERACK

---
 src/net_processing.cpp | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/net_processing.cpp b/src/net_processing.cpp
index 853c488bed..43447a2c34 100644
--- a/src/net_processing.cpp
+++ b/src/net_processing.cpp
@@ -2213,6 +2213,12 @@ bool ProcessMessage(CNode* pfrom, const std::string& msg_type, CDataStream& vRec
     // Feature negotiation of wtxidrelay should happen between VERSION and
     // VERACK, to avoid relay problems from switching after a connection is up
     if (msg_type == NetMsgType::WTXIDRELAY) {
+        if (pfrom->fSuccessfullyConnected) {
+            // Disconnect peers that send wtxidrelay message after VERACK; this
+            // must be negotiated between VERSION and VERACK.
+            pfrom->fDisconnect = true;
+            return false;
+        }
         if (pfrom->nVersion >= WTXID_RELAY_VERSION) {
             LOCK(cs_main);
             if (!State(pfrom->GetId())->m_wtxid_relay) {
-- 
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